This invention relates to aluminas of the pseudoboehmite type which are suitable for incorporation into catalysts composed of Y zeolites and a matrix containing clay and such aluminas.
The aluminas which have been employed are selected to produce zeolite catalysts which have suitable resistance to attrition. The problem has been addressed and discussed in Secor et al. U.S. Pat. No. 4,010,116, Lim, et al., U.S. Pat. No. 4,206,085, and in copending applications of which one of us is a co-applicant in applications Serial No. 138,544, and Serial No. 173,064.
The pseudoboehmite aluminas which when employed in the zeolite-clay-alumina systems which have been found most suitable to produce catalysts having a desirable attrition resistance have been designated as Type A aluminas (See Lim et al., supra, U.S. Pat. No. 4,206,085). Such aluminas are also identified in said Liu, et al. applications as those having a Peptization Index of less than 60, and preferably less than about 30. (See Appendix.)
In the copending applications, procedures are described for producing pseudoboehmites having suitable peptization index values for use in zeolite-clay-alumina catalyst systems, based on the neutralization of an acid aluminum salt with ammonium hydroxide.